1. Technical Field
The present invention relates to a liquid vessel having a liquid lead-out portion for ejecting liquid and a flexible liquid containing portion formed of a film for containing liquid, and a method of manufacturing the liquid vessel.
2. Related Art
There is a liquid ejecting apparatus which includes a liquid container and a liquid ejecting head, ejects liquid output from the liquid container from the liquid ejecting head, and discharges the liquid to a target which faces the liquid ejecting head. An example of such a liquid ejecting apparatus is an inkjet recording apparatus.
A variety of inkjet recording apparatuses including a carriage, a recording head functioning as a liquid ejecting head mounted in the carriage and an ink cartridge functioning as a liquid container have been developed.
Such inkjet recording apparatuses supply ink from the ink cartridge to the recording head and discharge the ink from a nozzle formed in the recording head, while the carriage is moved relative to the recording medium as a target, thereby performing printing with respect to the recording medium.
Among such inkjet recording apparatuses, there is a configuration in which the ink cartridge is not mounted in a carriage (called an off carriage type), in order to reduce load on the carriage or downsize the apparatus. Such an ink cartridge includes an ink pack for containing ink and a casing for containing the ink pack.
FIG. 11 is a conventional example of the ink pack.1 1 FIGS. 11-14 should be labeled as “Conventional” or “Prior Art” if prior art under at least one section of 35 U.S.C. §102.
The ink pack 100 is disclosed in JP-A-2005-59320 and includes a cylindrical liquid lead-out portion 101 for ejecting ink and a flexible liquid containing portion 102 formed of a film for containing the ink.
The liquid lead-out portion 101 is formed of a hard resin material and has a valve tool which is mounted in an inkjet recording device and opens a flow path when an ink supply needle of the recording apparatus is inserted thereinto.
As shown in FIGS. 12 to 14, the liquid containing portion 102 has a vessel structure including a first sealing portion 121 obtained by welding both ends 111c and 111d of a film 111 including a lamination structure of a metal film 111a and a resin film 111b for a gas barrier property to each other to form a body portion 113, a gore portion 123 placed under tension in a circumferential direction of the body portion 113 at side surfaces thereof by a pair of mountain-shaped folding portions 115a and 115b folded at opposed side surfaces of the body portion 113 in a longitudinal direction and a valley-shaped folding portion 116 between the pair of mountain-shaped folding portions 115a and 115b, a second sealing portion 125 for sealing an opening 113a of the body portion 113 in a state in which the liquid lead-out portion 101 is inserted into the opening 113a of one side of the body portion 113, and a third sealing portion 127 for sealing an opening 113b of the other side of the body portion 113.
The sealing portions 121, 125 and 127 are sealed by thermal welding in a state in which the surfaces of the resin films 111b of the film 111 overlap with each other.
However, in an inkjet recording apparatus for business use, in order to reduce the replacement frequency of the ink pack 100 due to an ink shortage to improve the operation rate of the apparatus, a large-capacity ink pack 100 is required.
If the capacity of the ink pack 100 is increased, rigidity of the liquid containing portion 102 needs to be increased by thickening the film 111 in order to prevent the film 111 from being damaged due to low strength.
However, a liquid containing portion 102 having high rigidity due to thickening of the film 111 is difficult to deform due to a restoring force of the film 111 which may cause inconvenience.
For example, in the conventional ink pack 100, since the liquid containing portion 102 before use is completely filled with ink, as shown in FIG. 15, the gore portion 123 perfectly expands such that the pair of mountain-shaped folding portions 115a and 115b are unfolded so that internal angles thereof are close to about 90 degrees. Then, the gore portion 123 is difficult to fold even when storage amount is reduced by the consumption of the ink. When the liquid containing portion 102 is pressurized from the outside by pressurized air such that the ink in the liquid containing portion 102 is supplied from the liquid lead-out portion 101 to the recording apparatus, the peripheral portion of the gore portion 123 is difficult to crush. Thus, there is a problem that the amount of residual ink is increased.
If the film 111 used in the liquid containing portion 102 is thinned in order to prevent the above-described problem from occurring, for example, the ink is shaken at the time of transport and the gore section is repeatedly bent. In this case, cracking occurs in the metal film 111a configuring the film 111, the gas barrier property of the liquid containing portion 102 is reduced, and the storage property of the stored ink deteriorates.